Is the 2ºC limit enough? An interview with Prof. van Ypersele

There are many climatologists on our planet, some of them are truly standing out. Jean-Pascal van Ypersele, professor at UCL in Belgium, and Vice-chair of the IPCC, definitely belongs to those few. This is because he combines scientific authority and rationalism with a human heart of compassion and understanding for our world. I asked Prof. Ypersele about his opinion on the recent G8 decision to adopt 2ºC as the maximum for average global warming.

Prof. van Ypersele, you have witnessed the climate change debate since a long time. Now, finally, the G8 officially announced that they accept 2ºC as a target for maximal global warming. Many people are breathing a big sigh of relief, and believe that we finally are on the right track. Are we?

Well, it is interesting to see the G8 recognizes that the target set by the European Union 13 years ago (Council of European Ministers, June 1996) has wide support. It is an important step in the right direction, even if science (and climate) has significantly evolved since 1996. The last IPCC assessment report (2007) has shown that the risks to a number of natural and human systems were assessed to be significantly higher for a 2°C global warming than they were assessed in the previous IPCC assessment (2001). If the same European ministers who decided to consider a warming above 2°C as dangerous were to revisit their decision today using the same criteria, they would very likely have to conclude, on the basis of the latest IPCC report, that the threshold would have to be lower than 2°C by about half a degree. So, we are on a better track than previously, but there is still a long way to go.

So what do you believe is needed to have a reasonable chance of avoiding a destabilization of our climate, and what do you see as „reasonable“?

Climate is already destabilized, so the question should rather be „how much do we need to reduce global emissions to prevent a warming larger than a dangerous threshold“. If we take for a moment the 2°C target as a reference, the IPCC indicated that to stay just above this value (not „under“ it!), we needed to have global reductions of the order of 50 to 85% by 2050 compared to 2000. If the target was to stay below a value lower than 2°C, the reductions needed would be even larger. Whether that is reasonable or not is for policymakers to decide, but the IPCC has shown that many technologies, policies, and changes in behaviour were possible to achieve deep reductions.

How realistic is it, in your opinion, that we will achieve those measures?

The IPCC has shown repeatedly that technical and social measures were available at relatively low cost, and that the key missing element was political will to implement them.

In your opinion, what is the most important thing that each one of us can do to increase the probability that we avoid a global climate catastrophe?

Ask the decision makers at all level how they take the climate challenge into account in their decisions, and make them accountable for their actions.

Is there anything else you would like to add?

Climate is only one of the large challenges faced by humanity. Biodiversity loss, lack of access to basic water and energy, large inequities between populations and regions are at least as important as climate change.

Even taking all these into account, I am convinced that „Yes, we can“.

Thank you very much, Prof. van Ypersele. And thank you for all your efforts to help us move towards a sustainable future, hopefully in time.